I have a Kindle DX and I think the primary problem is that 3G isn't working. I have been through three levels of support with amazon, now I'm waiting for an Engineer to get in touch with me... I'm wondering if anyone here has any suggestions though, as the support people I spoke to didn't seem particularly knowledgeable (although they were very polite and responsive I'll admit).

The Problem

Primarily 3G seems to be buggered, it seems to try to connect but just gets no connection and turns off again. This means I can't register my kindle (it was registered, but I tried a factory reset).
Last book read and a few other things don't seem to be persisting, although it's possibly because of the 3G issue.

Some things I have tried

Restarting the device via Settings > Menu > Restart

Restarting the device by holding power for 30 seconds

Resetting the device to factory default via Settings > Menu

I updated the firmware (to 2.5.8) and tried all of the above

311 from settings: Scans for carriers but then doesn't show a list and goes straight back to the settings screen

411 from settings: The "Radio Serial Number" is blank, "Roaming Version Number" is -1. If I turn 3G on before doing it, then it waits saying "Retrieving data" until 3G goes off again.

611: Says "Sorry – WAN info is not available at this time"

I definitely have mobile coverage, I used to be able to access 3G here (and I can from my phone). My problems just started one day and I haven't been able to connect to 3G anywhere since then.

I have a Kindle DX and I think the primary problem is that 3G isn't working. ...
Primarily 3G seems to be buggered, it seems to try to connect but just gets no connection and turns off again. This means I can't register my kindle (it was registered, but I tried a factory reset).[*] 311 from settings: Scans for carriers but then doesn't show a list and goes straight back to the settings screen[*] 411 from settings: The "Radio Serial Number" is blank, "Roaming Version Number" is -1. If I turn 3G on before doing it, then it waits saying "Retrieving data" until 3G goes off again.[/LIST]

The 311 screen not finding any carriers says that either you are out of cellphone range, or there is a problem with your 3G hardware. It is possible that the 3G carrier you were using is no longer visible at your location. Perhaps a new building is blocking the signal.

You could try taking it to a different location several miles (or km) away and try 311 again...

Of course, the 411 info would be blank if you had wireless turned off. It IS on, right?

I'm in Cornwall, UK. Over the last couple of days I've lost 3G on my DX, it's defaulting to GPRS, which is slooooow. It could have happened before then - I keep wireless off until I need it. I've been wondering if it's to do with the O2 problems, if you're in the UK, it could be the same issue. If so I imagine that it'll cure itself when O2 fix their problems.

I'm in Cornwall, UK. Over the last couple of days I've lost 3G on my DX, it's defaulting to GPRS, which is slooooow. It could have happened before then - I keep wireless off until I need it. I've been wondering if it's to do with the O2 problems, if you're in the UK, it could be the same issue. If so I imagine that it'll cure itself when O2 fix their problems.

No. Amazon use Vodafone in the UK, not O2. Possibly a problem with your local Vodafone mast - 3G service does go off from time to time. If it's not restored in a few days, I'd report it to Vodafone.

Well Amazon has determined that it's faulty, but because it's out of warranty it will cost $150USD to replace... I think I can live without 3G unless I can repair it myself.

I have just been through the process this morning with Kindle Support. They stated that because I did not have info for the "Radio Serial Number:", the internal modem is broken and cannot be repaired.

Unfortunately I had performed a "Factory Reset" prior to contacting them which has reset my DX to the default including not being registered which now means I cannot use the "Collections" function locally anymore :-(

I have just ordered a new one which should hopefully be here in a few days.

Am now scouring this site to see if there is any other way to get "Collections" working locally.

During my hunting session today, I actually discovered Kindle Collections and have installed it. I have also now jail-broken my Kindle DX and used a registration hack to locally register it and now the Collections function is once again available.

That being said, I will actually use Calibre (with Kindle Collections)to control the content on my Kindles from now on anyway.

Many thanks to the posters in MobileRead for the information I have garnered to assist me.

I have just been through the process this morning with Kindle Support. They stated that because I did not have info for the "Radio Serial Number:", the internal modem is broken and cannot be repaired.

Something similar happened to me with a K4.

One of my K4s had gotten bricked, and I developed the "simple debricking" method to debrick it. It had somehow gotten its mmc contents scrambled during an official firmware update, including where the serial number and other identifying info. After I restored this information (incorrectly) from a backup copy, it would not register (but it apparently confused the amazon servers and corrupted my records in their database). I discovered my bad data and reflashed it using the correct values from a backup copy, but it STILL would not register. After reaching a "high level" tech at amazon, he confirmed that my kindle's database record in their system contained an invalid "serial number and MAC address pairing". After he fixed that in their system, my kindle was able to register again, but mysteriously, its previous "Special Offers" status went away and my special offers screensavers reverted back to the factory "dead authors" screensavers.
The point of this story is that perhaps something similar happened to your DX (corrupt registration server database record), and only an amazon tech that can modify your record in their registration server can get it to register again.